Film projector with rotatable turret head



1950 v. E. PRATT ETAL 2,517,414

FIUI PROJECTOR WITH RQTATABLE 'TURRET HEAD Original Filed larch 7, 1945 '7 Sheets-Sheet l FIEJ- ATTORNEYS V. E. PRATT ET AL FILI PROJECTOR WITH ROTATABLE TURRET HEAD 7 Sheets-Sheet 2 ATTORNEYS Aug. 1, 1950 Original Filed March 7, 1945 m 3 m. h w v m m .u.

Augw L 1950 v. E. PRATT ETAL 2,517,414

mu PROJECTOR wrm ROTATABLE TURRET HEAD ATTORNEYS Aug. 1, 1950 v. E. PRATT ETAL FILM PROJECTOR WITH ROTATABLE TURRgT HEAD Original Filed March 7, 1945 7 Sheets-Sheet 4 ATTORNEYS '7 Sheets-Sheet (3 V. E. FRA'IT ET AL FIUI PROJECTOR WITH ROTATABLE TURRET HEAD Qriginal Filed larch 7,, 1945 HNVE BY WM 9 E950 v. E. PRATT mm. ,51%

FILM PROJECTOR WITH RQTATABLE TURREZ K-EAD Original Filed March I, 1945 7 Sheets-Sheet "1' ATTC RNEYS Patented Aug. 1, 1950 UNITED STATES PATENT OFFICE Verneur E. Pratt and George F. Gray, Norwalk, Conn.

Original application March 581,354. Divided and 7, 1945, Serial No. this application August 26, 1947, Serial No. 770,710

8 Claims. 3

This invention relates to improvements in projectors, and is directed more particularly to the provision of a reading machine for microfilm or the like, including means for producing enlarged prints of any desired frame.

The present application is a division of the copending application Serial Number 581,354, filed March 7th, 1945.

An object of the invention is the provision in a projector of a novel film gate or pressure plate which consists of a curved transparency adapted to be positioned in the machine in one position for projecting negatives, and adapted to be reversed ior projecting positives. In each of the aforementioned positions the negative or the positive microfilm emulsions are not in contact with the gate or pressure plate and, therefore, the emulsions do not become scratched.

Yet another object of the invention is the provision in a microfilm reading machine of a casing, a turret mounted thereon carrying film advancing mechanism, a film gate or pressure plate, and a condensing lens system, said turret being freely movable on said casing to a plurality of positions, and illuminating means in said casing and depending from said turret, so that illumination is supplied to the turret regardless of its position.

An object of the invention is the provision in a projector of means for projecting an image downwardly, means in said projector for reflecting said image laterally upon a screen in a side wall of said projector and the provision of a second mirror movable to, or away from, a position to refiect said image horizontally in an opposite wall of said projector.

Other objects and advantages of the invention will be apparent to those skilled in the art upon a study of the accompanying drawings and the specification.

Referring to the drawings:

Figure 1 is a perspective view of our new and improved projector showing the turret on the top and the viewing screen on one side thereof;

Figure 2 is a sectional elevation of the projector shown in Figure l, with the turret positioned as shown in Figure 1;: v

Figure 3 is a sectional elevation similar to Figure 2, except that the turret has been rotated 90 from the position shown in Figure 2 and also in which the printing mirror diverts the image to a sensitized surface carried on the rear wall of the projector;

Figure 4 is a reduced plan view of the turret showing the film gate or pressure plate positioned 2 for projecting negative film. The emulsion side of the film does not come in contact with the glass or other transparent material forming the film gate or pressure plate; 5 Figure 5 is a view similar to Figure 4, except that the film gate or pressure plate is turned to a reversed position so as to project positive film;

Figure 6 is a bottom view of the turret of Figure 4;

Figure 'l' is a sectional view taken along the line l'l of Figure 2, showing the indexing knob associated with the printing mirror;

Figure 8 is a plan view of one form of our pressure plate;

Figure 9 is a plan view of a modified form of the same;

Figure 10 is an elevation of a film gate or pressure plate with its supporting studs secured thereto to form a unitary structure;

Figure 11 is an enlarged cross sectional view of the mirror-objective lens unit;

Figure 12 is a plan view of the mirror-objective lens unit;

Figure 13 is a diagrammatic sketch showing the electrical circuits and controls in the projector;

Figure 14 shows a further modification of the invention wherein the pressure plate is stationary and the film is out of contact therewith while being moved and brought into contact therewith for projecting under control of solenoids; and

Figure 15 is a detailed view of one of the arms supporting the film rollers.

Referring first to Figure 1, the new and improved projector consists of a casing generally designated by the numeral 20. The front portion 21 of this casing is indented or recessed to support a viewing screen 22. On the front of the casing is a control handle 23 carrying a depending stud (not shown) which moves along in a slot 24 as the control handle is moved to the right or to the left. Associated with the stud on the control handle and mounted inside the casing is a control for the film feed which will 5 be hereinafter more fully explained in connection with Figure 13. On the right hand side of the casing 28 is a knob 25 which controls the supplying of current to the source of illumination.

The top wall 26 of the casing has a depression formed therein which will be described in connection with Figure 2. Rotatably supported in the depression is a plate 21 which will hereinafter be termed a turret plate.

Mounted on the turret plate in spaced relation 65 to each other are reel shafts 28 and 29. The reel shaft 28 may carry a reel 30 of film 31. A takeup reel 32 may be mounted on the reel shaft 29 and the film 31 secured thereto after it is passed through the film gate which will presently be described. The shafts 28 and 29 in their upper portions are preferably square so as to engage square holes in the reels and drive the same. The turret also carries a housing 33 for the mirror-objective cell and the film gate to be presently described; a housing 34 for the condensing lens system, has a finned portion 35 for the illuminating mirror to be presently described.

Referring now to Figure 2, which is a sectional elevation of the projector shown in Figure 1, the top wall 26 of the casing has an annular depression 36 formed therein leaving an annular shoulder 31 upon which the turret plate 21 rides. Suitable balls or other friction reducing elements (not shown) may be interposed between the ledge 31 and the turret plate 21 to facilitate the rotation of the turret. The turret plate 21 has a rectangular opening 38 formed therein. Mounted in the opening 38 is a first surface mirror 39 carried on a bracket 40 which is secured to the plate 21. A lamp housing 4| has its upper end flanged at 42 and this flange is secured to the lower face 21a of the turret plate 21 in any suitable manner, for example, by means of screws 43. The open end of the lamp house permits the delivery of light through the opening 38. Within the lamp house near the upper end thereof is a suitable bracing web 44 having a masked opening 45 formed therein.

In the lower portion of the lamp house is a socket 48 in which a lamp 41, which forms the source of illumination for the projector, is mounted. A conductor 48 leads from the socket 46 to a source of current and a light switch, which will be described in connection with Figure 13.

The turret plate 21 has a depression 49 formed therein, and supported in this depression is a condensing lens cell 58 which carries condensing lenses 51 and 52 with a spacer sleeve 53 therebetween. Also supported in the depression 49 is mounted a heat absorbing lens 54. Positioned on the turret plate 21 in front of the condensing lens (to the left of the condensing lens as seen in Figure 2) is our new and improved film gate or pressure plate 55 which will presently be described in detail. Mounted in a hole 56 formed in the turret plate 21 is the shank portion 51 of a mirror-objective lens element 58. This element includes a mirror 59 inclined at a 45 angle with the axis of the condensing lens cell 50. The shank portion 51 has its axis cutting the mirror at substantially a midpoint therein and adjustably carries an objective lens 58.

a The reel shaft 28 has a lower portion which is round, and which is journalled in a bushing 6| mounted in the plate 21. The lower portion 28a of the shaft 28 is journalled in a plate 62 carrying a small electric motor 63. A gear 64 is keyed to the shaft 28 and, meshing with the gear 64 is a pinion 65 carried on a shaft 66 which is journalled in the plate 82 and in the turret plate 21. Secured to the pinion 65 is a gear 61 which meshes with a pinion 68 carried on the motor shaft 69.

The reel shaft 29 is similarly arranged and has associated therewith gears, pinions, and an electric motor duplicating those just described in connection with the reel shaft 28, the motor being designated by the numeral 63 and the gears corresponding to the gears 64 and 61 being respectively designated as 64 and 61.

Positioned on the base 18 of the casing is a support or standard 1|, the upper portion 12 of which forms the support for a first surface mirror 13. This mirror is inclined to the right with the horizontal and normally receives the emergent beam from the objective lens 60.

A double faced surface mirror 14 is secured to a supporting shaft 15 suitably journalled in the side walls 19 and of the casing. This mirror has secured thereto a yoked member 16 (see Figure 7) which has a stud 11 extending into a slot 18 formed in the right side wall 88 of the casing. Concentric with the right end of the slot, as seen in Figure 2, a counterbore BI is provided. At the left end of the slot is formed a second counterbore 82. A shouldered screw threadedly engages a central hole in the stud 11. This screw has an enlarged head 84 which forms a working fit in a counterbore 85 formed in a knob 86. The shank 81 of this knob is of a diameter to form a working fit in the counterbore 8|. Within the counterbore B5 and surrcunding the shank of the screw 83 is a spring 88 which urges the knob toward the wall 80 of the casing.

The purpose of the slot 18 is to permit the mirror 14 to be swung within the cabinet to a plurality of positions which are defined by the engagement of the shank 81 of the knob 86 with the counterbore 8|, for one position of the mirror 14 or with the counterbore 82 for another position of the mirror.

A kidney-shaped shield 89 has a boss 98 with a hole therein which fits the shank 11. This shield is secured to the shank 11 in any suitable manner, for example, by means of a pin 9|, so that it always spans or covers the slot 18, thereby making the casing light-tight. When the mirror 14 is in the position shown in solid lines in Figure 2, light projected upon the mirror 12 by the objective lens 60 is reflected up to the surface 14*- of the mirror and this surface in turn reflects it to the screen 22.

The rear wall 92 of the casing has an opening 93 formed therein, and adjacent to the bottom edge of this opening is a locating strip 94. A door 95 is adapted to have its bottom edge positioned in engagement with the locating strip 94 and carries at the top a retaining spring 96 which engages the upper edge of the opening 95. A knob 91 is provided to facilitate the removal of the door 95. Mounted on the door, and extending through the opening 93 is a frame 98 which holds a pad 99 formed of light-sensitive paper, for example. The paper may be perforated in line with the opening I08 formed in the frame 98 with the exception of portions at the ends thereof which form tabs 101 to facilitate the removal of an exposed sheet from the block or pad 99.

When the mirror 14 is in the position shown in dot-dash lines, the second surface 1 l receives the emergent beam from the objective lens 60 and reflects it upon the block 99 within the opening I88 of the frame 98.

The film gate or pressure plate 55 is shown in detail in Figures 8 and 10. The film gate consists of a curved plate of glass or the like, the midportion I82 of which the curve is slightly flatter, as shown in Figure 8. This midportion lies in the field of the optical system, and although slightly curved, presents a practically fiat fleld for the portion of the film to be projected.

vof the stud I03 engaging the hole II2.

A mounting stud I03 has a slot Ill formed therein, and one end of the pressure plate is cemented in this slot. A second mounting stud I05 has a similar slot I05 which is cemented to the other endof the pressure plate 55. The stud I03 has a portion I01 of reduced diameter, thereby providing a shoulder I03. Likewise, the stud I05 has aportion I09 of reduced diameter defining a shoulder II which is in horizontal alignment with the shoulder I00.

In Figure 9 is shown a modified form of pressure plate 55. The midportion III is formed of a curve of a substantially longer radius than the radius of the body of the pressure plate, so as to provide a continuous curve and yet hold the film in intimate contact with the portion of longer radius, with the result that the field of the projected image is almost flat.

Referring again to Figure 10, the pressure plate 55 is mounted with the shank I00 of the stud I engaging the hole H3 and the shank I01 A reel 30 carrying negative film 3I- is positioned on the reel shaft 28. The film is let over a roller II4, then across to a second roller H5 in alignment therewith and thence the film passes on and is secured to the take-up reel 32. The rollers Ill and H5, as may be seen in Figure 4, are so positioned on the turret plate 21 that a line tangent to both rollers falls behind the surface of the pressure plate engaged by the film. Therefore, the tension on the film holds the film in contact with the surface of the pressure plate 55.

Now, in order to maintain a substantially uniform pressure of the film against the pressure plate 55, we employ a motor 53 tending to drive the take-up reel 32 in the direction of the solid arrow, and a second motor 53 is geared to the shaft 29 and tends to drive the reel 30 in the direction of the dotted arrow. This arrangement is described in our co-pending application Serial Number 539,740, filed June 10, 1944, now Patent No. 2,412,551, dated December 10, 1946. The motors are connected together with a potentiometer between them so that as the current supplied to one motor is increased, the current supplied to the other motor is decreased with the result that the motor receiving the greatest amount of current drives the film, and the other motor acts as a brake. This arrangement will be more fully described in the circuit diagram, Figure 13.

Light from the condensing unit 50 passes through the pressure plate 55 thence through the film. It is then directed downwardly by the mirror 59 in the mirror-objective lens unit 58 and passes through the objective lens and onto the mirror 13 and the surface 14 of the mirror 14 and thence to the screen 22, where the image is to be viewed on the screen. If the image is one which it is desired to reproduce, the mirror 14 may be shifted to the dot-dash position (Figure 2) and the surface 14 of this mirror will direct the light to the surface of the pad 93. If the film to be projected is a positive film instead of a negative, the pressure plate 55 may be lifted out from the position shown in Figure 4, turned end for end, as shown in Figure 5, and reinserted with the shank of. the stud I03 engaging.

the hole II3. A reel 30 carrying film 3| is positioned on the reel shaft 29 and film 3| is threaded over the roller III, in contact with the rear of the pressure plate 55 and may pass over shown in Figure 5 it will be noted that a line I tangent to the upper surfaces of the rollers Ill and III lies forwardly of the pressure plate 55 so that when the take-up reel 32 is driven by its motor 63 and the reel 30 is braked or retarded by its motor 53, the positive film is firmly held in contact with the pressure plate 55. If the objective lens had previously been in focus with the negative film, it would have to be adjusted to compensate for the moving of the focal plane (the active surface of the pressure plate The mirror-objective lens mount 52 is shown in detail in Figures 11 and 12, Figure 11 being a sectional view seen along the lines II-II of Figure 12. The unit 55 includes a body portion II6 having a, shank portion 51 previously described as fitting in a hole 55 in the turret plate. The shank 51 is provided with tongues or keys H1 and H8 which engage corresponding slots formed in the hole 55 for properly orienting the mirror with the optical axis of the projector. The body portion IIG has a rectangular depression H9 formed therein and this depression forms a socket for the mirror 53. The interior bore of the shank 51 is provided with threads I20 which are engaged by corresponding threads on the barrel of the objective lens 50 so that the latter may be screwed in or out to focus the image on the screen 22 or on the surface of the block 33.

Figure 13 shows a wiring diagram wherein a pair of conductors are connected to a source of current I2I. These conductors lead to a switch I22, and leading from the switch is a conductor I23 which is connected to switch 25. A transformer I24 has a primary windin I25, one end of which is connected to the switch 25 and the other of which is connected to a conductor I25 leading from the switch I22. The transformer has a secondary winding I21, the terminals of which are connected to the projection lamp 41 by means of wires 48. The motor 63 has one terminal thereof connected via a wire I28 to one terminal of the motor 63'. The wire I23 is connected via wire I29 to the conductor I23. The motor 63 has its other terminal connected via wire I30 to one end of a resistance winding I 3I and the other end of the resistance winding is connected via a wire I32 to the other terminal of a motor 53. The resistance winding I3I is arranged so that the turns thereof may be contacted by a movable arm I33, and the movable arm is in turn connected via a. wire I 34 to the conductor I25. The movable arm I33 carries a slot I35 which is engaged by a depending stud I35 in the control handle 23. As the control handle is moved to the right or left along the slot 24 (Figure 1) the control arm I33 is swung in either direction, and thereby cuts a greater resistance in series with one of the motors and reduces the resistance in series with the other of the motors (the motors being 63 and 63").

As stated above, the motor having less resistance in series therewith operates to drive the film against the urge of the other motor, which has a greater resistance in series therewith, and thereby the last mentioned motor acts as a brake. The switch I22 controls all current going into the machine and the switch 25 controls the illumination of the projection lens 41.

Referring to Figure 14, which is a further modification of the invention, the turret plate 21 carries reel shafts 28 and 29 upon which are mounted reels 30 and 32 respectively. The shafts 25 and 29 are driven by motors exactly like those described above in connection with Figures 2 and 3.

The mirror and objective-lens holder 33 Is the same as is shown in Figure 4 and the'same condensing lens assembly ill is employed; Between the lens holder 53 and the condensing lens assembly 50 the turret plate 21 has holes H2 and H3, and the pressure plate 55 is mounted with the shank of the stud I engaging the hole H3 shaft 20 and the him is led over a roller I I4, then across to a second roller I It are mounted on the turret plate in a novel manner, and since both mountings and the associated elements are identical except that they are rights and lefts, it is only necessary to describe one of them:

The roller H5, as shown in Figures 14 and 15, is secured to an arm I31 by means of a shouldered screw I33 engaging a threaded hole therein ad- Jacent to one end thereof. The other end of the arm I31 is provided with a boss or hub I33 which is journalied on a shouldered screw I40 having threads I which engage a threaded hole in the plate 21. Intermediate the ends of the arms I31 is an upstanding boss I42 which carries a tapped hole which is engaged by a shouldered screw I43. A solenoid plunger, I44 has a flattened portion I46 at one end thereof and a bearing hole with suflicient clearance is formed thereinv and Q is engaged by the shank of the screw I43. A solenoid winding I46 is mounted on the turret plate 21 and the plunger I44 may reciprocate therein. A stop pin or boss I41 mounted in the plate 21 defines the normal position of the roller I I5 and a spring I48 having one end connected to a stud I50 in the plate 21 urges the arm I31 to itsnormal position.

As stated above, the roller supports are identical except for rightsand lefts', so the elements associated with the roller II4 will be given the same numerals as just described, with the addition of the letter a after eachnumeral.

It will be seen in Figure 14 that when the rollers H4 and H5 are in tleir normal positions. with their supportingarms I 31 and I31, respectivs ly, in contact with the stops I41!- and I41, the film just clears the face of the pressure plate I55. Thus, it can be seen that whether the emulsion is on the side of the film facin the pr ssure plate or on the side fa ing the objective lens unit, it cannot be scratched while it is being moved.

Now, whcn the film is at rest and is to l-e projected the cnergization of the solenoids I46 and I46 will effect the pulling inof the plungers I44 and I44 and thereby swingthe arms I31 and I31 upwardly, as viewed in Figure 14, to the positions shown in dot-dash lines, stops I5I and I52 also being provided for defining these positions.

When the rollers are in these positions, a tangental line spanning them passes well behind the face of the pressure plate, and the opposite pull of the motors on the shafts 28 and 29 pulls the film taut so that it is spanning the slightly curved surface of the pressure plate under tension and will. therefore, make a good projection. As soon as the solenoids I46 and I41 arctic-energized, the springs I48 and I48 immediately pull the arms I31 and I31 downwardly until they contact the stops I41 and I41, respectively, and the film is ready to be moved again.

Now. for conveniently operating and controllingthe film food and solenoids, the stud I 36 projecting inwardly from the control handle 23 may, in an endwise manner, bear against a pair of thereby de-energizing the solenoids and allowing the rollers H4 and H5 to immediately assume the normal Positions, so that as the control arm is moved in either direction, the film may be moved in either direction without being in actual contact with the pressure plate 55.

Although we have described a preferred embodiment of the new and improved projector, it

is obvious that many changes may be made in the arrangement herein shown and described without departing from the spirit of the invention as defined in the following claims.

What is claimed is:

1. In a device of the character described, a turret forming a support, a lamphouse depending from said support, an aperture formed in said support and communicating with the interior of said lamphouse, a lamp in said lamphouse for delivering light via said aperture, an optical system on said support including a reflector adjacent to said aperturefor receiving vertical rays of light from said lamp and turning them horizontally, a second reflector spaced apart from said first'reflector for receiving the horizontal rays and directing them angularly with respect to the horizon, condenser means between said reflectors, a

reversible pressure plate one surface of which is curved and adapted to define a focal plane, and

film supporting and advancing means on said support adapted to advance a film over said surface under tension in either direction.

2. The invention according to claim 1, in which said second reflector is mounted in a cell supported in said turret and carrying an objective lens for receiving said angularly directed rays.

3. In a device of the character described, a turret forming a support, a lamphouse depending from said support, an aperture formed in said support and communicating with the interior of said lamphouse, a lamp in said lamphouse for delivering light via said aperture, an optical system on said support including a reflector adjacent to said apertutre for receiving vertical rays of light from said lamp and turning them horizontally, a second reflector spaced apart from said first reflector for receiving the horizontal rays and directing them downwardly, condenser means between said reflectors, a reversible pressure plate one surface of which is curved and adapted to define a focal plane, and film supporting and advancing means on said support adapted to advance a film over said surface under tension in either direction.

4. The invention according to claim 3 in which a keyed hole is formed in said support beneath said second reflector and in which a support for said last reflector includes a tubular boss fitted in said keyed hole and adapted to be bodily removed therefrom, and in which an interior bore in said boss is substantially concentric with said keyed hole and carries an objective lens.

5. The invention according to claim 3 in which said film supporting and advancing means includes a pair of rollers spaced apart from each other and so positioned with respect to said pres- 9 sure plate that a tangental line Joining the surfaces of said rollers is nearer to said condenser means than to said surface when the pressure plate is in one position and is nearer to said second reflector than to said surface when said pressure plate is reversed.

6. The invention according to claim 3 in which said film supporting and advancing means includes a pair of rollers spaced apart from each other and so positioned with respect to said pressure plate that a film extending between said rollers and in contact with said surface is ironed out" against said surface for both positions of said pressure plate, and in which two reels adapted to support a film are operatively connected to motors tending to run in opposite directions and adapted to have energy supplied thereto differentially.

7. In a device of the character described, a

turret forming a support, a lamphouse depending from said support, an aperture formed in said support and communicating with the interior of said lamphouse, a lamp in said lamphouse for delivering light via said aperture, an optical system on said support including a reflector adjacent to said aperture for receiving vertical rays of light from said lamp and turning them horizontally, a second reflector spaced apart from said first reflector for receiving the horizontal rays and directing them downwardly, condenser means between said reflectors, a reversible pressure plate one surface of which is curved and adapted to define a focal plane, a removable housing mounted on said turret and embracing said first reflector and said condenser means and spanning said pressure plate, said housing cooperating with said lamphouse to confine the light, and film supporting and advancing means on said support adapted to advance a film over said surface under tension in either direction.

3. A device according to claim 7 in which a second housing is mounted on said turret in cooperative relation with the portion of the latter spanning said pressure plate for enclosing said second reflector.

VERNEUR E. PRATT. GEORGE F. GRAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,889,575 Sebille Nov. 29, 1932 2,113,578 Draeger Apr. 12, 1938 2,125,582 Pratt et a1 Aug. 2, 1938 2,163,593 Draeger June 27, 1939 2,177,638 Draeger Oct. 31, 1939 2,265,992 Beck Dec. 16, 1941 2,279,463 Hopkins Apr. 14, 1942 2,332,810 Place Oct. 26, 1943 FOREIGN PATENTS Number Country Date 510,692 Great Britain Oct. 30, 1937 

